1. Field of the Invention
The present invention is in the field of packaging assemblies wherein articles to be packed are enclosed in a heat-shrinkable film while under compression, and the thus enclosed stack of articles is heated to cause shrinkage of the film about the stack, then cooled while being compressed to a positive repeatable fixed height dimension.
2. Description of the Prior Art
There are numerous examples in the prior art of heatshrinking a film about articles in order to provide a tightly fitting package. For example, in Weeks U.S. Pat. No. 2,402,476 there is disclosed a method in which bags are inserted into an outside covering bag, and then pressed together preparatory to closing the bag into position to act as a bale to contain the bags and hold the compression.
Zelnick U.S. Pat. No. 3,662,512 describes a method wherein a sleeve of heat-shrinkable film is applied around a pallet load with its open end extending above the pallet load and its open bottom extending below the pallet. The top and bottom portions of the sleeve are initially shrunk to lock the sleeve onto the pallet load and the pallet, and subsequently the intermediate portion of the sleeve is shrunk.
Muskat et al. U.S. Pat. No. 3,031,809 describes another method and apparatus for packaging with a heat-shrinkable material, involving the use of a specifically designed blank composed of relatively stiff paper.
Kammer U.S. Pat. No. 3,555,772 describes a continuous method for packaging newspaper stacks involving the use of individual weights on each stack during the heat shrinking procedure.
James U.S. Pat. No. 3,362,128 describes a method of packaging articles in which a heat-shrinkable film is wrapped around an aligned stack of packaged articles, the wrapped stack is compressed and the stack is heated to shrink the film into conformity with the stack.